I once lived in a place that allowed dogs and one of my neighbors had a chiwawa and a german shepard. she was in a wheel chair and worked so she could not always walk the dogs three times a day so besides training them for outside she also litter box trained them and pad trained them . until recently she used her blue and white pads that go under her incase of accidents with her bag. Her pet Pads are now bought in the pet isles of most stores. they are like the pads they have for putting underneath incontinent people in wheel chairs, beds. (blue and white in color) they absorb urine and she would put the used ones in a plastic bag with some pet fresh sprinkled in there to control the odor until she could take the garbage out at night.